tree-walk.c

   1 #include "cache.h"
   2 #include "tree-walk.h"
   3 #include "tree.h"
   4
   5 void *fill_tree_descriptor(struct tree_desc *desc, const unsigned char *sha1)
   6 {
   7         unsigned long size = 0;
   8         void *buf = NULL;
   9
  10         if (sha1) {
  11                 buf = read_object_with_reference(sha1, tree_type, &size, NULL);
  12                 if (!buf)
  13                         die("unable to read tree %s", sha1_to_hex(sha1));
  14         }
  15         desc->size = size;
  16         desc->buf = buf;
  17         return buf;
  18 }
  19
  20 static int entry_compare(struct name_entry *a, struct name_entry *b)
  21 {
  22         return base_name_compare(
  23                         a->path, a->pathlen, a->mode,
  24                         b->path, b->pathlen, b->mode);
  25 }
  26
  27 static void entry_clear(struct name_entry *a)
  28 {
  29         memset(a, 0, sizeof(*a));
  30 }
  31
  32 static void entry_extract(struct tree_desc *t, struct name_entry *a)
  33 {
  34         a->sha1 = tree_entry_extract(t, &a->path, &a->mode);
  35         a->pathlen = strlen(a->path);
  36 }
  37
  38 void update_tree_entry(struct tree_desc *desc)
  39 {
  40         void *buf = desc->buf;
  41         unsigned long size = desc->size;
  42         int len = strlen(buf) + 1 + 20;
  43
  44         if (size < len)
  45                 die("corrupt tree file");
  46         desc->buf = buf + len;
  47         desc->size = size - len;
  48 }
  49
  50 static const char *get_mode(const char *str, unsigned int *modep)
  51 {
  52         unsigned char c;
  53         unsigned int mode = 0;
  54
  55         while ((c = *str++) != ' ') {
  56                 if (c < '0' || c > '7')
  57                         return NULL;
  58                 mode = (mode << 3) + (c - '0');
  59         }
  60         *modep = mode;
  61         return str;
  62 }
  63
  64 const unsigned char *tree_entry_extract(struct tree_desc *desc, const char **pathp, unsigned int *modep)
  65 {
  66         void *tree = desc->buf;
  67         unsigned long size = desc->size;
  68         int len = strlen(tree)+1;
  69         const unsigned char *sha1 = tree + len;
  70         const char *path;
  71         unsigned int mode;
  72
  73         path = get_mode(tree, &mode);
  74         if (!path || size < len + 20)
  75                 die("corrupt tree file");
  76         *pathp = path;
  77         *modep = canon_mode(mode);
  78         return sha1;
  79 }
  80
  81 void traverse_trees(int n, struct tree_desc *t, const char *base, traverse_callback_t callback)
  82 {
  83         struct name_entry *entry = xmalloc(n*sizeof(*entry));
  84
  85         for (;;) {
  86                 struct name_entry entry[3];
  87                 unsigned long mask = 0;
  88                 int i, last;
  89
  90                 last = -1;
  91                 for (i = 0; i < n; i++) {
  92                         if (!t[i].size)
  93                                 continue;
  94                         entry_extract(t+i, entry+i);
  95                         if (last >= 0) {
  96                                 int cmp = entry_compare(entry+i, entry+last);
  97
  98                                 /*
  99                                  * Is the new name bigger than the old one?
 100                                  * Ignore it
 101                                  */
 102                                 if (cmp > 0)
 103                                         continue;
 104                                 /*
 105                                  * Is the new name smaller than the old one?
 106                                  * Ignore all old ones
 107                                  */
 108                                 if (cmp < 0)
 109                                         mask = 0;
 110                         }
 111                         mask |= 1ul << i;
 112                         last = i;
 113                 }
 114                 if (!mask)
 115                         break;
 116
 117                 /*
 118                  * Update the tree entries we've walked, and clear
 119                  * all the unused name-entries.
 120                  */
 121                 for (i = 0; i < n; i++) {
 122                         if (mask & (1ul << i)) {
 123                                 update_tree_entry(t+i);
 124                                 continue;
 125                         }
 126                         entry_clear(entry + i);
 127                 }
 128                 callback(n, mask, entry, base);
 129         }
 130         free(entry);
 131 }
 132
 133 static int find_tree_entry(struct tree_desc *t, const char *name, unsigned char *result, unsigned *mode)
 134 {
 135         int namelen = strlen(name);
 136         while (t->size) {
 137                 const char *entry;
 138                 const unsigned char *sha1;
 139                 int entrylen, cmp;
 140
 141                 sha1 = tree_entry_extract(t, &entry, mode);
 142                 update_tree_entry(t);
 143                 entrylen = strlen(entry);
 144                 if (entrylen > namelen)
 145                         continue;
 146                 cmp = memcmp(name, entry, entrylen);
 147                 if (cmp > 0)
 148                         continue;
 149                 if (cmp < 0)
 150                         break;
 151                 if (entrylen == namelen) {
 152                         memcpy(result, sha1, 20);
 153                         return 0;
 154                 }
 155                 if (name[entrylen] != '/')
 156                         continue;
 157                 if (!S_ISDIR(*mode))
 158                         break;
 159                 if (++entrylen == namelen) {
 160                         memcpy(result, sha1, 20);
 161                         return 0;
 162                 }
 163                 return get_tree_entry(sha1, name + entrylen, result, mode);
 164         }
 165         return -1;
 166 }
 167
 168 int get_tree_entry(const unsigned char *tree_sha1, const char *name, unsigned char *sha1, unsigned *mode)
 169 {
 170         int retval;
 171         void *tree;
 172         struct tree_desc t;
 173
 174         tree = read_object_with_reference(tree_sha1, tree_type, &t.size, NULL);
 175         if (!tree)
 176                 return -1;
 177         t.buf = tree;
 178         retval = find_tree_entry(&t, name, sha1, mode);
 179         free(tree);
 180         return retval;
 181 }
 182